Incorrect advice from researchers from Harvard School of Public Health suggests people should swap saturated fats and carbohydrates for linoleic acid (omega 6) in order to reduce cardiovascular disease.
The 2014 research (1) is still top of Googlesearch and advises that “Swapping saturated fat and carbohydrates for linoleic acid – the main polyunsaturated fat found in vegetable oil, nuts, and seeds – lowers risk of coronary heart disease”.
Let’s get some things straight – swapping saturated fat (which is cream, butter, lard, animal fat) and, instead, using polyunsaturated fats (for example, canola, safflower oil, sunflower oil, corn oil, soybean, and cottonseed oil, which all contain linoleic acid) may be an improvement but is not ultimately a clever idea. At the end of their article they advise using the Mediterranean Diet and using Olive oil – a much better idea since it contains little linoleic acid.
No wonder people seeking health advice get confused!
There are three groups of oils and fats – monounsaturated (e.g. Olive oil); polyunsaturated (e.g. vegetable and seed oils) and saturated fats and oils (e.g. meat, dairy etc). A fat is just a solid form of the oil. Fats are often referred to as fatty acids – hence linoleic acid is a fat.
Havard TH Chan School of Public Health detailed an interview with the researchers – their comments may not be the greatest advice. Harvard Health should know better.
Firstly, the researchers included olive oil as a polyunsaturated oil – it is not. It is primarily a monounsaturated oil. It also contains less than 10% Linoleic acid.
Secondly, seed oils are the main culprits – they invariably contain high levels of Linoleic acid. For exampl:
Highest Linoleic acid oils
Importantly, Linoleic acid is also referred to as omega-6.
Linoleic Acid can lead to chronic inflammation, promoting illness
Unfortunately, there’s a problem. Linoleic acid is converted readily in the body to arachidonic acid, from which we form highly inflammatory hormones called eicosanoids – for example, one group is arthritis-causing prostaglandins. Arachidonic acid can also form thromboxanes.
So, the net effect of an intake of Linoleic acid can be inflammatory prostaglandins, blood clotting and an increase in leukotrienes, another of the most inflammatory groups of compounds you can have in your body. Oh, and eicosanoids play a role via Cox-2 in driving cancer. Linoleic acid promotes oxidation of LDL-C and increases atherosclerosis (2). Linoleic acid can also increase metabolic syndrome (3). Linoleic acid also enhances angiogenesis – the provision of blood supplies to cancer (4).
Olive oil, fish oils
Olive oil contains little Linoleic acid. It is known, along with fish oils, to increase levels of gut bacteria and make high levels of anti-inflammatory molecules. Olive oil reduces metabolic syndrome (5)
Chronic illness occurs when the ratio of omega 6 to omega 3 increases; this is particularly seen in cancer (6). Fish oils are long chain omega 3; plants and seeds, apart from Linoleic acid, contain short chain Omega 3. There is little crossover.
Inflammation equals disease. It is the precursor to all chronic illness. Anti-inflammatory molecules protect your health.
Editor’s Note: We publish this to help promote good health amongst our readers. We find it mystifying that Harvard should be promoting this research, and that the fact checkers at Google have the Harvard study at the top, on page 1 of search.
- Farvid MS, Ding M, Pan A, Sun Q, Chiuve SE, Steffen LM, Willett WC, Hu FB. Dietary Linoleic Acid and Risk of Coronary Heart Disease: A Systematic Review and Meta-Analysis of Prospective Cohort Studies. Circulation. 2014
- Folcik VA, Cathcart MK (1994) Predominance of esterified hydroperoxy-linoleic acid in human monocyte-oxidized LDL. J Lipid Res 35: 1570-1582.
- Renaldi O, Pramono B, Sinorita H, Purnomo LB, Asdie RH, et al. (2009) Hypoadiponectinemia: a risk factor for metabolic syndrome. Acta med Indones 41: 20-24.
- Linoleic acid enhances angiogenesis through suppression of angiostatin induced by plasminogen activator inhibitor 1; BJC, Oct 2011; 105; – https://www.nature.com/articles/bjc2011434
- The importance of the ratio of omega-6/omega-3 essential fatty acids; Biomed Pharmacother; 2002, Oct; 56(8). A Simopoulos, Dept Genetics and Nutrition, Washington – https://pubmed.ncbi.nlm.nih.gov/12442909/#affiliation-1